The invention herein relates to a method for making non-woven fiber pads which are needled to form a thick material known as "shoddy". This material is useful as padding in furniture and within automobile upholstery and as soundproofing material within automotive bodies and the like.
Such non-woven material or "shoddy" is commonly made of fibers obtained from recycling or tearing apart rags. Thus, conventionally the material is produced by shredding or tearing apart rags or other cloth to obtain the loose fibers. These fibers are then passed into garnets, which are fiber distributors that lay fibers upon a collection belt located between them.
Conventionally, a number of garnets are located above the collection belt. Each garnet lays the fibers in a generally parallel, thin layer either transversely of the belt or alternatively in a limited length, longitudinal direction of the belt. Thus, the garnets form layers of oriented or parallel fibers, one layer upon another. The fibers of each layer are generally of the same directional orientation and are transverse to the fibers of the next adjacent layer. The resulting lamination of fiber layers generally resembles the formation of plywood, with each ply being thin and directionally oriented transversely to the ply above and below it.
The layered, relatively thick blanket produced by the garnets upon the conveyor is then conventionally carried through a needling apparatus. This apparatus generally comprises a platen having a large number of closely spaced or densely packed needles arranged to penetrate through the blanket. The needling platen may be applied against a back-up platen located on the opposite side of the blanket or alternatively, at times, a pair of needling platens may be used, with the two opposing each other.
The needling platen or platens move up and down rapidly so that the fabric is repeatedly hit by the needles which penetrate through the fabric. These needles displace the fibers and cause them to intertwine for interlocking the fiber layers together. These needles may be either straight pointed needles or alternatively, may have a barb-like pointed tip for increasing the intertwining of the fibers during each stroke of the needling platen.
Each increment or portion along the length of the blanket is repeatedly penetrated by the needles so that the resulting pad is formed by randomly oriented, intertwined fibers which make the pad relatively dimensionally stable both as to thickness and as to its planar dimensions. The resulting pad may then be either rolled up for shipment to the user or alternatively may be cut into pieces for particular desired uses.
The above-described procedure for manufacturing shoddy is limited by the productive capabilities of the garnets which operate relatively slowly. That is, in general, each garnet involves a mechanism that traverses the carrier conveyor belt to lay down the fibers. The movement of the garnet or the distribution part of the garnet is relatively slow so as to limit production. In addition, a failure of any garnet in a multi-garnet line can shut down the equipment. Garnets themselves, require maintenance and thus, additional service labor.
In the past, it was believed that a blanket could not be effectively needled, without tearing it apart, unless the blanket is formed of uni-directional or oriented fiber thin layers. In the absence of layering, the needling, which takes place rapidly and with the needles moving transversely of the blanket, tends to tear or rip apart the blanket. Thus, the garnets have been considered to be essential to the production of this kind of padding even though it would be desirable to eliminate them for the reasons mentioned above as well as for other reasons. However, until now, no practical way had been conceived for eliminating the garnets and the layering effect required by the garnets.